Dominant Enhancers of Egfr in Drosophila melanogaster: Genetic Links Between the Notch and Egfr Signaling Pathways

摘要

The Drosophila epidermal growth factor receptor (EGFR) is a key component of a complex signaling pathway that participates in multiple developmental processes. We have performed and F1 screen for mutations that cause dominant enhancement of wing vein phenotypes associated with mutations in Egfr . With this screen, we have recovered mutations in Hairless ( H ), vein, groucho ( gro ), and three apparently novel loci. All of the E(Egfr) s we have identified show dominant interactions in transheterozygous combinations with each other and with alleles of N or Su(H) , suggesting that they are involved in cross-talk between the N and EGFR signaling pathways. Further examination of the phenotypic interactions between Egfr, H , and gro revealed that reductions in Egfr activity enhanced both the bristle loss associated with H mutations, and the bristle hyperplasia and ocellar hypertrophy associated with gro mutations. Double mutant combinations of Egfr and gro hypomorphic alleles led to the formation of ectopic compound eyes in a dosage sensitive manner. Our findings suggest that these E(Egfr) s represent links between the Egfr and Notch signaling pathways, and that Egfr activity can either promote or suppress Notch signaling, depending on its developmental context.